1. Field of the Invention
The invention relates to a transmission for a motor vehicle, in particular an automated shift transmission, with a plurality of selectable and deselectable gear stages for implementing gear changes. The selection and deselection of the gear stages can be achieved by coupling units, in particular by engageable and disengageable sliding collars. The coupling units can be activated by shift rails and by respective actuators provided for this purpose, wherein particular gear stages are assigned to particular shift rails. The invention furthermore relates to a method for controlling a transmission. A plurality of gear stages can be selected and/or deselected in the transmission in order to implement gear changes. The selection and deselection of the gear stages is achieved with the aid of coupling units, in particular with the aid of engageable and disengageable sliding collars. The coupling units are activated by shift rails and by respective actuators provided for this purpose, wherein particular gear stages are assigned to particular shift rails.
Transmissions and methods for controlling transmissions for motor vehicles, wherein the transmissions have a given number of shift rails, are known. In these conventional transmissions, the shift rails are arranged such that they are effective, in terms of their operation, between the respective coupling units and the respective actuators. In other words, a coupling unit, which is preferably embodied as an engageable and disengageable sliding collar and with the aid of which the respective gear stage can be selected or deselected within the transmission, is actuated, via the shift rail, with the aid of the respective actuator, wherein the shift rail is arranged to be moveable within the transmission. As a result, the respective gear stage is either selected or deselected. In the conventional transmissions, specific gear stages are assigned to specifically corresponding shift rails. In this case, the first and the second gear stage are assigned to a first shift rail, the third and the fourth gear stage are assigned to a second shift rail and the fifth and the six gear stage are assigned to a third shift rail. In other words, the respective sequential gear changes between the first and second, the third and fourth gear etc. can be implemented with the aid of the first, second and third shift rail respectively by in each case correspondingly activating or moving just one shift rail.
Published, Non-Prosecuted German Patent Application No. DE 199 12 817 A1 discloses a device and a method in which a plurality of coupling units are provided within the transmission in order to reduce shifting times during gear changes, wherein the coupling units are separated from one another. In other words, the separate coupling units provided within the transmission, which can each be activated individually by separate actuators, preferably by Bowden cables, implement the individual gear changes within the transmission in a relatively short time since, in the case of sequential gear changes for example, when changing from first to second gear for example, two actuators and two coupling units are in each case activated simultaneously in order to implement the corresponding gear change. As a result, the shifting times here are correspondingly reduced.
In the case of the conventional devices and methods, i.e. in the case of the conventional transmissions, their control equipment is very complex and is therefore not only fault-prone but requires a correspondingly large amount of space when constructing the transmission in order to be able to implement the latter in an appropriate manner. Either, the control equipment for reducing the shifting times in conventional transmissions is very expensive and also fault-prone, such that it is impossible in this case to construct the transmissions in a compact way, or, the conventional transmissions can be constructed in a compact way and without complex control equipment but then have relatively long shifting times in the case of a gear change involving gear stages that are provided sequentially one after another.
It is accordingly an object of the invention to provide a transmission which overcomes the above-mentioned disadvantages of the heretofore-known transmissions of this general type and which reduces the shifting times for a gear change without the need for costly, fault-prone control equipment and which, at the same time, allows a compact construction of the transmission.
With the foregoing and other objects in view there is provided, in accordance with the invention, a transmission for a motor vehicle, including:
shift rails;
gear stages assigned to the shift rails such that respective successive ones of the gear stages are assigned to respective different ones of the shift rails;
the shift rails being configured such that, in a sequential gear change, respective ones of the shift rails are activated at least partially simultaneously;
coupling units operatively connected to respective ones of the shift rails and configured to select and deselect the gear stages for performing gear changes;
actuators operatively connected to respective ones of the shift rails; and
the coupling units being configured to be activated via respective ones of the shift rails and respective ones of the actuators.
In other words, the object of the invention is achieved, by a transmission for a motor vehicle, in particular an automated shift transmission, with a plurality of selectable and deselectable gear stages for implementing gear changes, the selection and deselection of the gear stages being achievable with the aid of coupling units, in particular with the aid of engageable and disengageable sliding collars, the coupling units being activatable by shift rails and by respective actuators, and particular gear stages being assigned to particular shift rails, wherein a plurality of gear stages is assigned to at least two different shift rails in such a way that the respective successive gear stages are assigned to different shift rails, with the result that the respective shift rails can be activated at least partially simultaneously in the case of a sequential gear change.
According to another feature of the invention, a first one of the shift rails has a first and a third one of the gear stages assigned thereto; and the first one of the shift rails is activated by a first one of the actuators.
According to yet another feature of the invention, a second one of the shift rails has a second and a fourth one of the gear stages assigned thereto; and the second one of the shift rails is activated by a second one of the actuators.
According to a further feature of the invention, a third one of the shift rails has a fifth one of the gear stages assigned thereto; and the third one of the shift rails is activated by a third one of the actuators.
According to yet a further feature of the invention, the third one of the shift rails further has a seventh one of the gear stages assigned thereto; and a fourth one of the shift rails has a sixth and an eighth one of the gear stages assigned thereto.
According to another feature of the invention, the shift rails, the coupling units and the actuators form a motor vehicle transmission configuration.
According to yet another feature of the invention, the shift rails, the coupling units and the actuators form an automated shift transmission configuration.
According to another feature of the invention, the coupling units are sliding collars configured to be engageable and disengageable.
With the objects of the invention in view there is further provided, a transmission configuration, including:
a first shift rail and a second shift rail;
a first gear stage, a second gear stage as a subsequent gear stage to the first gear stage, a third gear stage as a subsequent gear stage to the second gear stage, and a fourth gear stage as a subsequent gear stage to the third gear stage;
the first shift rail controlling the first gear stage and the third gear stage;
the second shift rail controlling the second gear stage and the fourth gear stage; and
the first shift rail and the second shift rail being simultaneously activated in case of a sequential gear change.
With the objects of the invention in view there is also provided, a method for controlling a transmission for a motor vehicle, the method includes the steps of:
providing gear stages assigned to at least two shift rails such that respective successive ones of the gear stages are assigned to respective different ones of the shift rails; and
performing gear changes by using coupling units activated via respective shift rails and respective actuators for selecting and deselecting the gear stages in the transmission and, in case of performing a sequential gear change, activating respective ones of the shift rails at least partially simultaneously in order to perform the sequential gear change.
In other words, the abovementioned object is achieved by a method for controlling a transmission for a motor vehicle, in particular a transmission as defined above, wherein a plurality of gear stages are selected and/or deselected in the transmission to implement gear changes, the selection and deselection of the gear stages being achieved with the aid of coupling units, in particular with the aid of engageable and disengageable sliding collars, the coupling units being activated by shift rails and by respective actuators, and particular gear stages being assigned to particular shift rails, wherein a plurality of gear stages is assigned to at least two different shift rails in such a way that the respective successive gear stages are assigned to different shift rails, with the result that the respective shift rails are activated at least partially simultaneously in the case of a sequential gear change.
Another mode of the method according to the invention includes the steps of activating a first shift rail by using a first actuator; and respectively selecting and deselecting a first gear stage and a third gear stage by using the first shift rail.
Yet another mode of the method according to the invention includes the steps of activating a second shift rail by using a second actuator; and respectively selecting and deselecting a second gear stage and a fourth gear stage by using the second shift rail.
Another mode of the method according to the invention includes the steps of activating a third shift rail by using a third actuator; and respectively selecting and deselecting a fifth gear stage and a seventh gear stage by using the third shift rail.
A further mode of the method according to the invention includes the steps of activating a fourth shift rail by using a fourth actuator; and respectively selecting and deselecting a sixth gear stage and an eighth gear stage by using the fourth shift rail.
Another mode of the method according to the invention includes the step of providing the coupling units as selectively engageable and disengageable sliding collars.
The invention is based fundamentally on the principle that, in a transmission with correspondingly provided shift rails, the respective gear stages are assigned to the various particular shift rails in a particular manner, namely in such a way that the gear stages that follow one another sequentially are provided on various, namely different, shift rails. This allows a partly simultaneous activation of the different shift rails on which the successive gear stages are provided and, due to the partially simultaneous activation of these different shift rails, the corresponding shifting time for the implementation of the gear change can be kept correspondingly short. As an advantageous result, short shifting times can thereby be achieved. Further, the number of shift rails in the transmission does not have to be increased and the control equipment does not have to be enhanced, in other words constructional outlay and corresponding costs are not increased, thereby avoiding the disadvantages mentioned at the outset.
There are many ways of refining and developing the transmission according to the invention and the method according to the invention in an advantageous manner.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a transmission and a method for controlling a transmission for a motor vehicle, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.